Switch for electrical fuel-feeding apparatus



g A. NAGEL swrrca run snowmen FUEL FEEDING APPARATUS Filed Auz. 4. 19254 Sheets-Shut 2 INVENTOR AUGUST NAGFL v 1,637,425 Aug. 2, 1927. A. NAGELSWITCH FOR ELECTRIQAL FUEL fEEDING APPARATUS I Filed Au. 4. 1 2 1 4Sheets'-Sheet .3

fi. Nage/ Y A. NAGE'L 4 Sheets-Sheet Aug. 2,1927.

swnca FOR ELECTRICAL FUEL FEEDING APPARATUS Filed Au. 4, 1925 w J 4/ wI, 11 11H 0 W Patented Aug. 2, 1927.

-UNITED STATES PATENT OFFICE.

AUGUST NAG-EL, OF STUT'IGART, GERMANY.

SWITCH FOR ELECTRICAL FUEL-FEEDING APPARATUS.

Application filed August 4, 1925, Serial No. 48,180, and in GermanyAugust 26,1924.

In electric pumps for the delivery of fuel or the like for the feedingof carburettors or the like, such for example as is described in UnitedStates Patent- No. 496,331 granted onthe 25th April, 1893, it isimportant that an absolutely reliable method of working be attained. Inorder to attain this, a switching device has been provided forelectrical fuel-delivering pumps the piston of which does not extendthrough the pump casing and is reciprocated by the alternate excitationof solenoid windings arranged round the pump chamber, and at the ends ofits strokes gives rise to a strengthening of the lines of force on theend surfaces of the pump chamber, as in my application Serial No.751,937, filed Nov. 24, 1924. This strengthening of the lines of forceattracts members which are located outside the pump chamber opposite tothe end faces of the pump and which are adapted to act in the mannerof amagnetic hammer break. The switching device is characterized by thefeature that the aforesaid members acting like a magnetic hammer breakconsist of double-armed levers rockable about sta tionary fulcra and areconnected with one another by a connecting rod. This rod has anattachment which is so shaped that during the moving to and ire of theconnecting rod it serves as a sliding support and an abutment with itsupper and under surfaces alternately, for one arm of a three-armedswitch lever, that is to say, it acts like a link motion or slidingguide. This result is attained owingv to the fact thata second.-

arm of the switch lever is constructed as a blade spring. The latterslides with its outer end between guides provided on the connecting rodof the pump members acting in the manner of a magnetic hammer break.Since the other arm of the switch is held fast, by means of a pin, bythe slide-guide acting as an abutment, until the reciprocating move mentof the connecting rod has reached its end in one direction or the othera stress is imparted to the switch spring, which suddenly straightens itas soon as the eflect of the sliding guide on the switch arm whichco-operates therewith ceases. By this means there also results thereversal of the pin of the switch lever, from one sliding surface of thecam-like sliding guide to the other. The third arm of theswltch lever,which is directed oppositely to the blade spring, is provided at its endwith a double-sided contact. It, is simultaneously rocked in common withthe other arms, thereby removing its contact from the co-acting contactof one solenoid circuit, while the contact located on the other side ofthe switch-lever arm. comes at the next instant into contact with thecorre, sponding contact of the circuitof the other solenoid.

Since the liquid delivered by the electric solenoid pump flows to ameasurin tank, and any overflowing thereof must fle prevented, a floatis provided in the measuringtank. This float, by a suitable arrangementof controlling and locking means puts the pump switch and consequentlythe pump itself out of operation when the measuring tank is filled. I l

The float is provided for this purpose with a rod. This rod carries,outside the measuring chamber, two pins. One or other of these pins,shortly before the termination of the upward or downward movement of thefloat, comes into contact with one end of one or other of twodouble-armed levers. The levers are connected with one another by ahelical spring at the ends of the levers remote from these co-actingpoints. On each of the lever arms connected by the spring is provided astop which is adapted to engage in front of a projection on a rotatabledisc. This disc serves to support at its centre a bent lever. The upperbent end of this lever is adapted to lock the end of the switch arm thatbears against the surfaces of the cam-like sliding and abutment memberoving to and fro with the connecting ro of the pump members that operatein the manner of a magnetic hammer break. By this means it prevents thesaid arm and consequently also the other arms of the switch lever romcontinuing their rocking or re versing movements. After the emptying ofs the measuring chamber has been effected the said locking leversuddenly releases this switch lever arm. This latter result is ob taindby. the fact that the bent locking lever or'its carrying disc isequipped with a blade spring, which slides through a guide consisting oftwo pins located on the float rod between the aforementionedlever-actuating pins. During the upward or downward movement of thefloat, that is, during the t filling or emptying of the measuring tank,

one [of these guide pins acts upon the said blade spring and subjects itto a bending stress until the blade spring is released. This occurs assoon as either the upper or the lower lever-actuating pin on the floatrod bears against the upper or lower toothed lever, rocks the latter,and thereby brings it out of engagement with the disc carrying theswitch-arm locking lever. At the moment of release the blade springstraightens itself and rocks the bent locking lever. When the latter hasthereby passed out of reach of the end of the switch arm the latter isreleased for reversal and the other pump solenoid circuit closed, aspreviously described The operation of the pump can then recommence andthe fuel be again delivered to the measuring tank and so forth.

In order to attain this the new construction hereinafter described indetail is provided.

'The same is illustrated in one constructional example in theaccompanying drawings.

Figure 1 shows the switching apparatus which is fitted to an electricpump, in the position in which the magnet core or piston of the pump isabout to be moved from right to left in the pump chamber.

pump controlled thereby.

The method of working of the apparatus 'is as follows As the switchposition in Figure 1 shows, the current flows through the left-handsolenoid coil a, and consequently the piston I) located in the pumpcylinder is moved towards this side. At the close of its movement itcomes to the end wall a of the pump, brings the lines of force up totheir maximum value, and causes the reversing rod gear d to move to theright. The blade spring e slidably supported between pins (5 and d onthe rod gear is bent in the opposite direction, as indicated indot-anddash lines. This bending of the blade spring (3 is only possibleowing to the fact that the T-shaped carrying member thereof is guidedwith its limb e, by the pin e or the like located thereon, u n the uppersurface of a guide or link (i which moves to the right with thereversing rod, and may be integral withit (see Figures 4 and 5).

During this guiding and blade-spring stress ing the contact stud eprovided on the third I limb e has remained in connection with thecontact stud k of the circuit of the left-hand solenoid a. When thereversing rod gear 03 in moving to the right has reached its endposition, the pin e slides oif its guide (see- .Figure 6), the bladespring a straightens itself into alignment with the limb 6 shown .indot-and-dash lines in Figure 1, and the circuit of the right-handsolenoid is closed, as the contact 6 now bears upon the associatedcircuit contact is. The position of the T-shaped member 6 illustrated inFigure 7 shows its configuration and position at the last instant beforereversal into the position shown in full lines, that is, when thereversing rod gear d has just moved to the left.

Now since the liquid delivered by the electrically operated solenoidpump flows to a the termination of the upward and downward movements ofthe float, with two double-armed levers g, 72, respectively. The saidlevers are connected with one another by a helical spring. The leverarms which are coupled together in this manner have eachv atooth g, hrespectively, and'these teeth alternately take up positions in front ofthe projections 73 2' respectively upon a disc 2', which is rotatableabout a pivot.

This disc serves at its centre as a support for a bent lever i 'Nowwhile the pump is working owing to the excitation of the solenoids aalternating in rapid succession, fuel is supplied from the pump chamberby the piston b to the measuring tank, as shown in Figure 8.

From this figure it will be seen that when the piston b isvmov-ing fromleft to right in the pump chamber, on the left-hand side of the pumpchamber liquid is drawn by suc- I tion out of the main tank, which isnot shown in the drawings, through the piping Z into the valve chamberm, and from there through the pipe 7%, the valve cone 0 being lifted 01fits seat 0 During this suction of the liquid a pres- I I sure is exertedby the piston b upon the liquid on the right hand side of the pumpchamber and that in the'pipe'p connected therewith,

and also in the valve chamber 1*, and the liquid is supplied through thepiping s, 8 to the measuring tank t, Figure 8.v During this action thevalve cone u has been lifted off its seat u while the valve cone to,which bears upon its valve seat in the neighbouring valve chamber 1),owing to the pressure of the liquid that passes into the latter throughthe pipe 8, and also in consequence of its own weight, assisted ifdesired by a light spring,

prevents this liquid from flowing through to the valve chamber m.

When the movement of the piston Z) is reversed, that is, when it ismoving from right to left in the pump chamber, a change-over ot' theliquid occurs, the liquid passing through the piping Z to the valvechamber a by lifting the valve cone 7 from the seat into the valvechamber q, and from there through the-pipe p to the right hand pumpchamber, but passing out of; the left hand pump chamber through the pipeveto the valve chamber m, and by lifting the valve cone to off its seat10 into the chambers '12 and r and through the pipes s and s to themeasuring tank t.

Owing to the constant supply of liquid to the measuring tank 23, aspreviously described, the float f rises in the measuring chamber, andwith it the rod f is also raised, and a blade spring i which extendsfrom the shaft of the disc 11 carrying the bent lever 2' as far as therod 7, is bent upwards by a pin 7 located on the rod 7 and therebystressed, as the disc 5 is prevented from rotating by the tooth whichengages in front of the projection 2. The stress to which the bladespring is subjected increases until the pin f presses against the end ofthe arm 9 of the locking lever '9, so that the lever rocks, and thetooth g 'is moved out of engagement with the projection 77. This takesplace at the moment when the column of liquid in the measuring chamberhas reached its highest level.

till

There then follows the straightenin of the blade spring 2'1, with therotating 0 the disc 2' thereby, so that the bent lever 2' moves into itslocking position in relation to the switch arm a, as shown in Figure 2.

Since in the instance illustrated the aforementioned switch arm e shownresting above the upper bend of the lever i the contact arm a with itscontact e, was

evidently on its way to the circuit contact is of the right-handsolenoid a oi the pump.

The contact arm e now remains in an id'e position between the circuitcontacts 70, k until sutficient fuel has been removed from the measuringtank.

At the time when the rocking of the bent lever i is accomplished by thestraightening of the blade spring 91*, as previously indicated, thetooth k on the lever It takes up a position during this rotary movementin front of the projection i on the-disc '8.

Now as the fuel escapes from the measuring vessel, during the sinking ofthe float f,

the latter now presses with a pin f on its rod f against the bladespring 2' and con-- sequently subjects it to a stress. Finally the pin flocated at the upper end of the float rod f comes against the arm h ofthelever it, bringing the tooth if out of engagement with the projection2' on the disc 2', and thereby releases the stressed blade spring 2'.Under these circumstances a rotation of the disc 2' takes place in aclockwise direction. The bent lever i is moved away from the rockingswitch arm 6 and the switch spring 0 which, as will be seen from Figure2, is still partially stressed, straightens itself out, and therebybrings the contact 6* up to the circuit contact 70.

The deliver of liquid by the pump is then resumed, and the disc 2'carrying the bent lever i is again locked against rotation by means ofthe tooth g and the projection i l/Vhat I claim is 1. Switchingapparatus for electrical fueldelivering apparatus and the like,comprising a magnetizable reciprocating member, two solenoids forreciprocating said member, and means for energizing said solenoidsalternately, said means comprising a mov= able switch member, areversing rod, magnetic means for displacing said reversingrod upon themagnetizable reciprocating member reaching either end of its stroke, an

abutment on said reversing rod, the movable switch member being adapted.to engage with said abutment during displacement of the reversing rodand to be released thereb at the end of said displacement, and resi ientmeans for changing the position of the movable switch member as soon assaid switch member is released by the abutment,

said resilient means being stressed by the displacement of the reversingrod.

2. Switching apparatus for electrical fuelnetizablo reciprocating memberreaching each end of its stroke, guiding means on said rod between whichthe said spring arm can slide, an abutment on the reversing rod, acircult changing contact stud on one rigid:

arm of the switch member, a" projecting member on the other rigidarm ofthe switch member, said projecting member being adapted to engagewithlsaid abutment dur ing displacement of the reversing rod and to bereleased thereby at the end of said dis-.

placement, the spring arm of the switch";

member being bent by the means magnetic means for displacing saidreversing rod upon the magnetlzable reclprocating member reaching eitherend of its stroke, an abutment on said reversing red, the mov ableswitch member being adapted to engage with said abutment duringdisplacement of the reversing rod and to be released thereby at the endof said displacement, resilient means for changing the position of themovable switch member as soon as said switch member is released by theabutment, said resilient means being stressed by the displacement of thereversing rod, means for locking the movable switchmember in anintermediate position-in which neither of the solenoids is energized,and means for bringing said locking means into action automatically assoon as the surface level of the fuel reaches a predetermined height andkeeping it operative until said level sinks again.

4. Switching apparatus for electrical fueldelivering apparatus and thelike, comprising a magnet-izable reciprocating member,

two solenoids for reciprocating said member, and means for energizingsaid solenoids alternately, said meansicom'prislng a mova-ble switchmember, a. reversing rod, magnetic meansrfor displacing-said reversing I'rod upon the magnetizablereciprocating member reaching either end ofits stroke,

an abutment'on said reversing rod, the movdisplacement of the reversingrod, a rotat-' able locking member, a locking arm secured thereto, saidlocking arm being adapted in one. position of said. rotatable member tomove-into the path of the movable switch member and prevent it fromenergizing either of the solenoids, a spring secured at one end to: saidrotatable member, a float inthe liquid, a float rodsecured to saidfloat, guiding means -on said float rod between which'said spring canslide, said guiding means tending to rotate the rotatable member throughthe medium of the spring as the surface level of the liquid rises andfalls, a' pawl capable of engaging with the rotatablemember to preventit from rotating in one direction, a second pawl capable of engagingwith said rotatable member to prevent it from rotating in the oppositedirection means provided on the float rod for disengaging one of thepawls when the float has risen to a predetermined level to enable therotatable body to move the locking arm into its operative position,andmeans provided on the float rod for disengaging the other pawl whenthe float'has sunk a predetermined'distance' below the said level toenablevthe rotatable body to move the looking arm out of its operativeposition.

1 In test'mony whereof I have signed my name to this specification.

AUGUST N AGEL.

